Tiled solar module repair process

ABSTRACT

In an example, a method includes providing a photovoltaic string comprising a plurality of from 2 to 45 strips, each of the plurality of strips being configured in a series arrangement with each other, each of the plurality of strips being coupled to another one of the plurality of strips using an electrically conductive adhesive (ECA) material, detecting at least one defective strip in the photovoltaic string, applying thermal energy to the ECA material to release the ECA material from a pair of photovoltaic strips to remove the defective photovoltaic strip, removing any residual ECA material from one or more good photovoltaic strip, aligning the photovoltaic string without the damaged photovoltaic strip, and a replacement photovoltaic strip that replaces the defective photovoltaic strip, and curing a reapplied ECA material on the replacement photovoltaic strip to provide the photovoltaic string with the replacement photovoltaic strip.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a non-provisional of U.S. Provisional ApplicationNo. 62/349,541, filed Jun. 13, 2016, and this application also claimspriority to U.S. patent application Ser. No. 14/609,307, filed Jan. 29,2015, which is incorporated by reference herein for all purposes.

BACKGROUND OF THE INVENTION

The present invention is directed to photovoltaic systems andmanufacturing processes and apparatus thereof In particular, the presentinvention provides an apparatus and method for using a replacementprocess of a selected solar strip, among a plurality of strips, for ahigh-density solar module.

As the population of the world has increased, industrial expansion hasled to a corresponding increased consumption of energy. Energy oftencomes from fossil fuels, including coal and oil, hydroelectric plants,nuclear sources, and others. As merely an example, the InternationalEnergy Agency projects further increases in oil consumption, withdeveloping nations such as China and India accounting for most of theincrease. Almost every element of our daily lives depends, in part, onoil, which is becoming increasingly scarce. As time further progresses,an era of “cheap” and plentiful oil is coming to an end. Accordingly,other and alternative sources of energy have been developed.

In addition to oil, we have also relied upon other very useful sourcesof energy such as hydroelectric, nuclear, and the like to provide ourelectricity needs. As an example, most of our conventional electricityrequirements for home and business use comes from turbines run on coalor other forms of fossil fuel, nuclear power generation plants, andhydroelectric plants, as well as other forms of renewable energy. Oftentimes, home and business use of electrical power has been stable andwidespread.

Most importantly, much if not all of the useful energy found on theEarth comes from our sun. Generally, plant life on the Earth achieveslife using photosynthesis processes from sunlight. Fossil fuels such asoil were also developed from biological materials derived from energyassociated with the sun. For life on the planet Earth, the sun has beenour most important energy source and fuel for modern day solar energy.

Solar energy possesses many desirable characteristics; it is renewable,clean, abundant, and often widespread. Certain technologies developedoften capture solar energy, concentrate it, store it, and convert itinto other useful forms of energy.

Solar panels have been developed to convert sunlight into energy. Forexample, solar thermal panels are used to convert electromagneticradiation from the sun into thermal energy for heating homes, runningcertain industrial processes, or driving high-grade turbines to generateelectricity. As another example, solar photovoltaic panels are used toconvert sunlight directly into electricity for a variety ofapplications. Solar panels are generally composed of an array of solarcells, which are interconnected to each other. The cells are oftenarranged in series and/or parallel groups of cells in series.Accordingly, solar panels have great potential to benefit our nation,security, and human users. They can even diversify our energyrequirements and reduce the world's dependence on oil and otherpotentially detrimental sources of energy.

Although solar panels have been used successfully for certainapplications, there are still certain limitations. Solar cells are oftencostly. Depending upon the geographic region, there are often financialsubsidies from governmental entities for purchasing solar panels, whichoften cannot compete with the direct purchase of electricity from publicpower companies. Additionally, the panels are often composed of costlyphotovoltaic silicon bearing wafer materials, which are often difficultto manufacture efficiently on a large scale, and sources can be limited.

Therefore, it is desirable to have novel system and method formanufacturing solar panels.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to photovoltaic systems andmanufacturing processes and apparatus thereof. In particular, thepresent invention provides an apparatus and method for using areplacement process of a selected solar strip, among a plurality ofstrips, for a high-density solar module. There are other embodiments aswell.

In an embodiment, a method of manufacturing a solar module apparatusincludes providing a photovoltaic string, the photovoltaic stringcomprising a plurality of from 2 to 45 strips, each of the plurality ofstrips being configured in a series arrangement with each other, each ofthe plurality of photovoltaic strips having a substantially similarwidth and substantially similar length, the photovoltaic stringcomprising a first bus bar and a second bus bar, each of the pluralityof strips being coupled to another one of the plurality of strips usingan electrically conductive adhesive (ECA) material to mechanicallyconnect the plurality of strips together, detecting the presence of atleast one defective strip in the photovoltaic string, applying thermalenergy to the ECA material to change a state of the ECA material torelease the ECA material from a pair of the photovoltaic strips toremove the defective photovoltaic strip, removing any residual ECAmaterial from one or more good photovoltaic strip that was adjacent tothe defective photovoltaic strip in the string, aligning thephotovoltaic string without the damaged photovoltaic strip, and areplacement photovoltaic strip that replaces the defective photovoltaicstrip, and curing a reapplied ECA material on the replacementphotovoltaic strip to provide the photovoltaic string with thereplacement photovoltaic strip.

In an embodiment, the method includes aligning a first portion of thephotovoltaic string to an alignment member, applying the ECA material onthe replacement photovoltaic strip, aligning a second portion of thephotovoltaic string to the replacement photovoltaic strip, and curingthe reapplied ECA material.

The ECA material may be a thermosetting acrylate adhesive, and the ECAmay be a heat cured adhesive that is loaded with conductive metalparticles. The thermal energy may be provided by conduction, convention,or radiation to a temperature ranging from 150 to 300 degrees Celsius,and in an embodiment heat may be provided by conduction using a heatsource that is heated to from 150 to 250 degrees Celsius.

In an example, each of the photovoltaic strips is derived fromseparating a solar cell into five strips of similar size and shape.

In an example, the defective photovoltaic strip has a defect consistingof at least one of a crack, a broken section, a bad electricalinterconnect, a defective photovoltaic material, or short or opencircuit.

In an example, detecting the presence of the at least one defectivestrip includes applying DC power to the first bus bar and the second busbar to initiate an emission of electromagnetic radiation from each ofthe photovoltaic strips, capturing an image of the photovoltaic stringto identify at least one of the photovoltaic strips that has a darkerimage and therefore a defective photovoltaic strip than a goodphotovoltaic strip to identify the defective photovoltaic strip.

In an example, the image is captured in an electromagnetic radiationrange including infra-red.

In an example, the good photovoltaic strip emits a substantially evenimage that has been captured and is homogeneous along an entirety of asurface region of the good photovoltaic strip. The DC power may be avoltage ranging from 10 to 50 Volts and a current ranging from 0.5 to 10Amps.

In an example, the photovoltaic string is configured with a plurality ofphotovoltaic strings in a module before a lamination process.

In an example, the thermal energy is provided selectively to localizeheat to the ECA material, while maintaining other portions of the stripsubstantially free from thermal energy.

In an example, after the thermal energy is applied to the ECA,mechanical force is applied to a joint which is bonded by the ECAmaterial to mechanically separate the defective strip from a portion ofthe string that includes non-defective strips.

In an example, the portion of the string that includes non-defectivestrips is retained in a fixture, and the defective strip is exposed byan orifice of the fixture.

In an example, the thermal energy is applied to the joint by placing thejoint in contact with a heated structure.

In an example, the mechanical force is a force moment that is applied byrotating the portion of the string that includes non-defective stripsrelative to the defective strip.

In an example, the replacement strip is an end strip of a second stringportion comprising a plurality of non-defective strips.

In an example, the ECA bonds an upper surface of a first string to abackside surface of a second string in an overlapped joint.

In an example, a solar module apparatus is provided. The apparatus has aplurality of strings, each of the plurality of strings being configuredin a parallel electrical arrangement with each other and a plurality ofphotovoltaic strips forming each of the plurality of photovoltaicstrings. The apparatus has a first end termination configured along afirst end of each of the plurality of strings and a second endtermination configured along a second end of each of the plurality ofstrings. The module has an equivalent diode device configured betweenthe first end termination and the second end termination such that oneof the plurality of photovoltaic strips associated with one of theplurality of strings when shaded causes the plurality of strips (“ShadedStrips”) associated with the one of the strings to cease generatingelectrical current from application of electromagnetic radiation, whilea remaining plurality of strips, associated with the remaining pluralityof strings, each of which generates a current that is substantiallyequivalent to an electrical current while the Shaded Strips are notshaded, and the equivalent diode device between the first terminal andthe second terminal for the plurality of strips is configured to turn-onto bypass electrical current through the equivalent diode device suchthat the electrical current that was bypassed traverses the equivalentdiode device coupled to the plurality of strips that are configuredparallel to each other.

Many benefits can be achieved by ways of the present invention. As anexample, the present module can be made using conventional processes andmaterials. Additionally, the present module is more efficient thanconventional module designs. Furthermore, the present module, andrelated techniques provides for a more efficient module usage usingbypass diodes configured with multiple zones of solar cells. Dependingupon the example, there are other benefits as well.

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the remaining portions of thespecification and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a solar cell article according toan example of the present;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a first side view thereof;

FIG. 7 is a second side view thereof;

FIGS. 8-12 are illustrations of an edge photovoltaic strip according toan example of the present invention;

FIGS. 13-17 are illustrations of a center photovoltaic strip accordingto an example of the present invention;

FIGS. 18-20 illustrate a photovoltaic string according to an example ofthe present invention;

FIGS. 21-25 illustrate a solar module according to an example of thepresent invention;

FIG. 26 is a front view of a solar cell in an example of the presentinvention;

FIG. 27 is a side view of the solar cell, including bus bars, in anexample of the present invention;

FIG. 28 is an expanded view of a bus bar in an example of the presentinvention;

FIGS. 29-33 illustrate a solar cell under a cut and separation processaccording to an example of the present invention;

FIG. 34 is a top view of a photovoltaic string according to an exampleof the present invention;

FIG. 35 is a side view of the photovoltaic string according to anexample of the present invention;

FIG. 36 is a simplified diagram of a system according to an example ofthe present invention;

FIG. 37 illustrates a process for replacing a strip in a stringaccording to an example of the present invention;

FIG. 38 illustrates a separation device for separating a defective stripfrom a string according to an example of the present invention;

FIG. 39 illustrates a process for re-assembling a string after one ormore defective strip has been removed from the string according to anexample of the present invention;

FIG. 40 illustrates a fixture for re-assembling a string after one ormore defective strip has been removed according to an example of thepresent invention; and

FIGS. 41 and 42 illustrate elements of a separation device according toan example of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to photovoltaic systems andmanufacturing processes and apparatus thereof. There are otherembodiments as well.

Embodiments of the present invention provide system and methods formanufacturing high density solar panels. Embodiments of the presentinvention use overlapped or tiled photovoltaic strip elements toincrease the amount of photovoltaic material, thereby increasing anamount of power, while reducing an amount of series resistance losses inthe solar panel. It is noted that specific embodiments are shown forillustrative purposes, and represent examples. One skilled in the artwould recognize other variations, modifications, and alternatives.

Although orientation is not a part of the invention, it is convenient torecognize that a solar module has a side that faces the sun when themodule is in use, and an opposite side that faces away from the sun.Although, the module can exist in any orientation, it is convenient torefer to an orientation where “upper” or “top” refer to the sun-facingside and “lower” or “bottom” refer to the opposite side. Thus, anelement that is said to overlie another element will be closer to the“upper” side than the element it overlies.

While the following is a complete description of specific embodiments ofthe invention, the description should not be taken as limiting the scopeof the invention as defined by the claims.

In an example, the present invention provides a method of manufacturinga solar module, including a repair process. In an example, one of thelimitations of conventional cells is an inability to perform rework byreplacing strings when a photovoltaic cell or strip is broken. It is notunusual in standard manufacturing for a cell or strip to crack in astring. In an example, Technicians use a soldering iron to releaseribbon wires from a broken cell. They are then able to insert a new celland then re-solder the ribbon wires. Thus they have repaired a string.

A feature of strings according to embodiments of the present disclosureis the use of “Electrically Conductive Adhesive” (ECA). The ECA is acured adhesive polymer formulation that is highly loaded with conductivemetal particles. In some embodiments, the conductive metal is silver.The ECA may be a thermosetting acrylate adhesive. The adhesive may havemay be modified with one or more hardening components such as epoxy,phenol-formaldehyde, urea-formaldehyde, etc., that provide hardness andbonding strength. In an example, the ECA is a low temperature cure onepart adhesive.

Polymers are generally categorized as thermoplastic polymers andthermosetting polymers. Thermoplastic polymers are typically meltprocessed, and solidify when they are cooled. When a solidifiedthermoplastic polymer is exposed to heat, it melts, after which it canbe re-formed into a new shape and solidified again by cooling.Therefore, thermoplastic polymers can be processed multiple times bymelting and solidifying.

Thermosetting polymers form cross-links between polymer chains when theyare cured. These cross-links are typically promoted by a chemicalreaction, so that the thermosetting polymer sets, or cures, in apermanent fashion. Because the polymer molecules in a thermosettingpolymer are bonded to one another in the cured state, they do nottypically return to a viscous state when exposed to heat. Manythermosetting polymer systems, such as heat cured phenolics, willoxidize when exposed to temperature without softening. Thermosettingpolymers do not melt after they are set.

Solder is similar to a thermoplastic resin in that after it is applied,it can be melted when heat is applied a second time. Conventional bondsbetween solar cells are implemented using solder, so conventional solarassemblies can be reworked by melting and re-applying solder to thecells. However, because a thermosetting ECA that has been cured will notmelt when exposed to elevated temperatures, rework processes availableto soldered photovoltaic assemblies are not available to photovoltaicassemblies that use an ECA.

Conventionally, thermosetting polymers are removed using chemicalsolvents or mechanical removal processes. However, mechanical removalpresents substantial risk of damaging sensitive materials in aphotovoltaic assembly, and require high levels of precision toeffectively remove relatively thin and precisely located polymer bonds.Therefore, cycle times for purely mechanical removal techniques are toolong to be economically feasible. Chemical solvents are difficult toapply to the limited areas involved with defective strip replacement,and are difficult, expensive and dangerous to handle, as well ascarrying the risk of damaging other materials in an assembled string.Therefore, purely mechanical and chemical based rework processes are noteconomically feasible.

In an example, a method according to the present disclosure provides away to repair the string made with ECA. In an example, the methodincludes removing a defective cell from a string and replacing it with agood cell. The inventors of the present disclosure have discovered thatwhile certain thermosetting ECAs cannot be melted, they will soften withtemperature sufficient to facilitate an economically feasible reworkprocess, which is unexpected. While the ECA is soft, mechanical forcecan be applied to bend the string in a controlled manner, such that themechanical force breaks the bond between the cells. If the force isapplied correctly, then the broken cell can be removed without damagingthe other cells in the string.

In an example, temperature is a key component to removing a damaged cellor string. If the temperature is too low, the ECA will not soften enoughand there is a risk that cells (either the broken one or good ones) willbreak when mechanical force is applied to a string. If excessive thermalenergy is applied to an ECA, then the ECA may undergo a chemicalreaction which could negatively affect the adjacent cells to the cellthat is being repaired. Therefore, embodiments of the present disclosureinclude exposing an ECA to a temperature between 150 C to 200 CTemperatures substantially above this range risk causing damage, whiletemperatures below this range may not soften the ECA adequately tofacilitate removal. Typical solder melt temperatures for solders thatprovide sufficient mechanical and electrical properties to connectstrips are in the range of 250 C, which carries additional risks ofdamaging materials and causing injury compared to the ECA softeningtemperatures of 150 C to 200 C.

In an example, the method also includes a reassembly process ofconfiguring a replacement cell or strip into the disassembled string. Inan example, residual ECA is removed from the good strips at both ends ofwhere the broken strip was removed. ECA removal may be performed with asolvent such as isopropyl alcohol (IPA) and an applicator. In anexample, ECA is applied to an end of the string that has an exposed busbar and is applied to the replacement strip. In an example, the methoduses a semi-automatic dispensing system to control the location andvolume of adhesive that is dispensed. In an example, two separatedportions of the original string and the new replacement cell arere-assembled into a continuous string. In an example in which thedefective strip is located at the end of a string, a single separatedportion is present.

In an example, one or more separated portion is placed in a fixture tomaintain the overall string length, the cell-to-cell spacing, and theoverlap between strips. In an example, the fixture facilitates a +/−50micron tolerance on the cell pitch. In an example, the new orreplacement strip in the string is heated to a temperature that willcure the ECA within a predetermined time. Typically, the temperature isbetween 120 C and 150 Degrees Celsius. In an example, the other originalECA connections not associated with the replaced strip can be reheatedto the curing temperature without any adverse effects. Of course, therecan be other variations, modifications, and alternatives.

FIG. 1 is a front perspective view of a solar cell article according toan example of the present disclosure. This diagram is merely an example,and should not unduly limit the scope of the claims herein. One ofordinary skill in the art would recognize other variations,modifications, and alternatives. A solar cell 100 is shown. The solarcell 100 has a substrate member having a surface region. The surfaceregion is an aperture region exposing photovoltaic material. In anexample, the photovoltaic material can be silicon, polycrystallinesilicon, single crystalline silicon, or other photovoltaic materials.

In an example, the cell 100 has the surface region comprising a spatialregion and a backside region. The cell has a first end strip 102comprising a first edge region 104 and a first interior region 106 asprovided on the spatial region. In an example, the first interior region106 comprises a first bus bar 108, while the first edge region on thespatial region has no bus bar. In an example, the first end strip has anoff cut 110 on each corner. Each of the off cuts 110 is about 45 degreesin angle, and has a flat edge abutting a pair of edges at ninety degreesfrom each other, as shown.

After the first bus bar 108, the solar cell has a plurality of stripsprovided on the spatial region. As shown, each of the strips 112 has abus bar 114 along an edge furthest away from the first bus bar 108. Eachof the strips 112 is substantially rectangular in shape, and can beconfigured with edges at ninety degrees from each other.

In an example, the cell 100 has a second end strip 116 comprising asecond edge region 118 and a second interior region 120. In an example,the second interior region 120 comprises a second bus bar 122 such thatthe second bus bar and the bus bar 114 from one of the plurality ofstrips forms a gap defining a scribe region 124. In an example, thesecond edge region 118 comprises no bus bar.

In an example, the first end strip 102, the plurality of strips 112, andthe second end strip 116 are arranged in parallel to each other andoccupy the spatial region such that the first end strip, the second endstrip, and the plurality of strips consists of a total number of five(5) strips.

In an example, the backside region 126 comprises the second end strip116 comprising the second edge region 118. In an example, the secondedge region 118 has a second backside bus bar 126 such that the secondbackside bus bar 126 and the second bus bar 122 are provided betweenphotovoltaic material of the second end strip. FIG. 2 is a front viewthereof. FIG. 3 is a back view thereof. FIG. 4 is a top view thereof.FIG. 5 is a bottom view thereof. FIG. 6 is a first side view thereof.FIG. 7 is a second side view thereof.

FIGS. 8-12 are illustrations of an edge photovoltaic strip 800 accordingto an example of the present invention.

FIGS. 13-17 are illustrations of a center photovoltaic strip 1300according to an example of the present invention.

FIGS. 18-20 illustrate a photovoltaic string 1800 according to anexample of the present invention.

FIGS. 21-25 illustrate a solar module 2100 according to an example ofthe present invention.

FIG. 26 is a front view of a solar cell 100 in an example of the presentinvention.

FIG. 27 is a side view of the solar cell 100, including bus bars, in anexample of the present invention. The solar cell 100 includes aphotovoltaic substrate 2704, a conductive backing material 2702, andmetallized surfaces 2706 and 2708.

FIG. 28 is an expanded view of a bus bar region of a solar cell 100 inan example of the present invention.

In an example, the present invention provides a method of manufacturinga solar module. The method includes providing a substrate member havinga surface region. In an example, the substrate is a solar cell 100 asdescribed in the present specification. The solar cell 100 is made ofphotovoltaic material, which has various features.

Features of FIG. 28 will be explained with respect to the numberingprovided in FIG. 1. In an example, the surface region comprises aspatial region and a backside region, a first end strip 102 comprising afirst edge region 104 and a first interior region 106 as provided on thespatial region. In an example, the first interior region 106 comprises afirst bus bar 108, while the first edge region 104 on the spatial regionhas no bus bar, and a plurality of strips 112 as provided on the spatialregion. In an example, each of the strips 112 has a bus bar 114 along anedge furthest away from the first bus bar 108, a second end strip 116comprising a second edge region 118 and a second interior region 120,the second interior region 120 comprising a second bus bar 122 such thatthe second bus bar 122 and the bus bar 114 from one of the plurality ofstrips 112 forms a gap defining a scribe region 124, the second edgeregion 118 comprising no bus bar, the first end strip 102, the pluralityof strips 112, and the second end strip 116 arranged in parallel to eachother and occupying the spatial region such that the first end strip102, the second end strip 116, and the plurality of strips 112 consistsof a total number of five (5) strips 112, the backside region comprisingthe second end strip 116 comprising the second edge region 118, thesecond edge region 118 having a second backside bus bar 126 such thatthe second backside bus bar 126 and the second bus bar 122 are providedbetween photovoltaic material of the second end strip 116.

In an example, the method includes separating each of the plurality ofstrips 114. The method includes separating the first end strip 102, andseparating the second end strip 116 by scribing via the scribe region124 and removing the second end strip 116. Each of the separationprocesses can occur along a spatial direction of the substrate.

In an example, the method includes transferring the first end strip 102in a first magazine, transferring each of the plurality of strips 114into a second magazine or a plurality of magazines, and transferring thesecond end strip 116 into a second magazine. In an example, the methodincludes selecting each of the plurality of strips 114, and arrangingthe plurality of strips in a string configuration. The method thenincludes using the string in a solar module.

In an example, a substrate member comprises a silicon material, abackside region further comprising a first backside bus bar on a firstend strip, and a plurality of bus bars respectively formed on theplurality of strips.

In an example, the substrate member has a dimension of 156 mm plus orminus about two mm, but other embodiments are possible.

In an example, each of the strips has a desired width to be assembled inthe string configuration.

In an example, the plurality of strips are monolithically connected witheach other. In an example, each of the plurality of strips has an apertregion. Further details of the present invention can be found throughoutthe present specification and more particularly below.

FIGS. 29-33 illustrate a solar cell 100 under a cut and separation prosaccording to an example of the present intion. FIGS. 29 and 30 areisometric and front views that show a ibe region 2900 of a solar cell,including a kerf 2902 that is cutrough a backing material 2904 aaphotovoltaic material 29

FIG. 31 shows a cell 3100 that has been subjected to a separationprocess. The separated cell 3100 includes a first edge strip 3102, asecond edge strip 3104, and three strips 3106 from middle portions ofthe cell. FIG. 32 shows a backside view of the separated cell 3100, andFIG. 34 shows an isometric view of the separated cell 3100.

FIG. 34 is a top view of a photovoltaic string 3400 according to anexample of the present invention.

FIG. 35 is a side view of the photovoltaic string 3400 according to anexample of the present invention focused on a cell to cell overlap inthe string. The photovoltaic string includes a plurality of strips 3500that are bonded together by an ECA layer 3502. Each strip comprises abacking material 3504, which may be a thickness of aluminum, and aphotovoltaic material 3506. The ECA 3502 is bonded between a conductivemetallized layer 3510, which may be a bus bar, that is disposed betweenthe backing material 3504 and the photovoltaic material 3506. Theexposed ends of the strips 3500 show a kerf 3512 and a fracture plane3514 from a scribing and singulation process.

FIG. 36 illustrates a simplified system diagram according to an exampleof the present invention showing 24 modules connected to poweroptimizers that feed into an inverter and then out to the grid.

In an example, the present method and system utilizes a ⅕^(th) stripwidth versus ⅓^(rd), ¼^(th) or ⅙^(th) of a cell strip width based uponunexpected benefits and/or results, as shown in the table below.

PV Width Comment Width 78 52 39 31.2 26 mm Cell Current 4.5 3 2.25 1.81.5 lsc = 9A standard cell Fingers 80-200 80-150 80-120 80-100 80(Microns) Based on standard cell finger Shading  7.0%  5.8%  5.0%  4.5%  4% Finger shading Cell Utilization 98.7% 97.4% 96.2% 94.9% 93.6% 2 mmoverlap Placements 2X 3X 4X 5X 6X Over standard module Fill Factor   76%  77%   78%   79%   79%

In the table, width refers to the width of a strip after it has been cutfrom a cell. Current is the amount of current that a strip produces,which is directly proportional to the size of the strip. Fingers carrycurrent across a strip, while shading is the area of the strip shadowedby the fingers. Cell utilization is the amount of area in a string inwhich strips do not overlap one another. The number of placements is howmany strips are cut from a cell and placed in a string. Fill factor isthe efficiency of the photovoltaic material present in a string comparedto its maximum power producing potential.

In an example, modules are configured to have current and resistancecharacteristics that are similar to a conventional module (Voc, Vmp,Isc, Imp, Power). However, modules can be designed to have differentcharacteristics for different applications. For example, modules createdaccording to embodiments of this disclosure can be configured to havelower voltage and higher current for the solar tracking applications,and to have higher voltage and lower current for residential modulesthat interface with module power electronics.

In an example, the present method and design uses a 31.2 mm strip width,which optimizes module characteristics, as well as providing a currentand voltage similar to standard modules. This allows embodiments to takeadvantage of standard inverters, electronics, and mechanical features.

An example of a process 3700 for replacing a photovoltaic strip in astring comprising a plurality of strips will now be explained withrespect to FIG. 37. In a first step S3702, a defective strip isidentified in an assembled string. The defective strip may be identifiedby applying current to the string and observing infra-red emissions fromeach of the strips in the string.

A string with a defective strip is placed into a fixture 3800 at S3704.In an embodiment, as seen in FIG. 38, the fixture 3800 includes a baseportion 3802 and an orifice 3804 that are configured to accommodate astring 3806. The string 3806 is placed on the base portion 3802, and ismoved forwards through the orifice 3804, which is disposed at an end ofthe base portion, so that a joint 3808 that bonds a defective strip 3810is exposed by the orifice. Portions of the fixture are illustrated inmore detail in FIGS. 41 and 42, which show the base portion 3802 that isassembled with an end bar 3830 and side rails 3832. A gap between theend bar 3830 and the base portion 3802 defines the orifice 3804.

Heat is applied to the joint 3808 at S3706 to soften the ECA thatprovides an adhesive bond at the joint. In an embodiment, heat isapplied by placing the joint 3808 between a lower block 3812 and anupper block 3814, and one or both of the upper and lower blocks mayinclude a heating element 3816. When heat is applied to the joint 3808,care may be taken to prevent good strips from being exposed to heat. Inparticular, the string 3806 may be positioned so that the heated blocks3812 and 3814 are in physical contact with the defective strip 3810, butare not in physical contact with, or are in minimal physical contactwith good strips of the string.

The joint 3808 may be retained between the upper and lower blocks for apredetermined time at a predetermined temperature to soften the ECAholding the joint 3808 together. In an embodiment, the predeterminedtemperature is between 150 and 300 degrees Celsius. In anotherembodiment, the predetermined temperature is between 150 and 250 degreesCelsius, while in still another embodiment the predetermined temperatureis between 150 and 200 degrees Celsius.

When the ECA has been heated and softened, mechanical force is appliedto the joint 3808 to separate the defective strip from non-defectiveportions of a string at S3708. In one embodiment, the mechanical forceis applied by raising or lowering the end of the base 3802 that isfarthest from the blocks, thereby applying a force moment to the joint3808 and causing the softened joint 3808 to separate.

After the defective strip 3810 has been separated from the string 3806,if the defective strip is located at a far end of a string, then theprocess may proceed to step S3710. However, if the defective strip 3810is located in a middle part of the string 3806, then the remainingportion of the string to which the defective strip is still bonded, e.g.a second string portion 3822, is placed on the base 3802, and steps 3706and 3708 are performed on the remaining joint 3808 attaching thedefective strip. When this process is completed, the defective strip3810 is completely separated from non-defective strips, and can bedisposed of.

In another embodiment, the second string portion 3822 is first separatedfrom the defective strip 3810 by performing steps S3704 to S3708 so thatthe defective strip 3810 remains attached to the first string portion3802, and the defective strip 3810 is then removed from the first stringportion 3802 by repeating steps S3704 to S3708.

After the defective strip 3810 has been removed, parts of the cured ECAthat remain on exposed edges of non-defective portions the strip areremoved at S3710. The cured ECA may be removed by a solvent, amechanical instrument, or a combination of the two. For example, the ECAmay be removed by applying a solvent that attacks the ECA to anapplicator such as a fiber bundle or a porous polymer, and applying theapplicator to the remaining ECA.

The first string portion 3820, which comprises non-defective strips, isthen re-bonded to one or more non-defective (“good”) strip to create astring that does not have any defective strips in a process 3900. In oneembodiment, as defective strips are removed from strings, the remainingportions of the strings having non-defective strips are accumulated andre-assembled to create replacement strings. For example, if stringsconsisting of 7 strips are desired, then string portions of 3 and 4strips may be accumulated as defective strips are removed, and theseremaining string portions may be re-bonded to one another with ECA. Inanother example, when a single defective strip is removed, that strip isreplaced using the one or more good string portion that remains afterthe defective strip has been removed. In other words, defective stripscan be replaced directly with a good strip, or the remaining good stringportions can be retained and re-assembled.

FIG. 39 illustrates an example of a process 3900 for re-assembling astring after one or more defective strip has been removed from thestring. A first string portion comprising non-defective strips isaligned in a fixture at S3902.

FIG. 40 illustrates an example of a cross-section of a fixture 4000 forre-assembling a string after one or more defective strip has beenremoved. The fixture 4000 includes a base 4002, a tray 4004 that may beremovable from the base, a first end guide 4006, and a second end guide4008.

A first string portion 4010 is aligned with the fixture 4000 by placingit against the first end guide 4006 at S3902. Subsequently, uncured ECA4014 is applied to an edge of the second string portion 4012 that willbe overlapped with and bonded to a corresponding edge of the firststring portion 4010.

After the ECA 4014 has been applied to the second string portion 4012,the second string portion 4012 is aligned to the first string portion4010 by placing it against the second end guide 4008, and is loweredonto the first string portion 4010. Although not shown in thecross-sectional view, the fixture 4000 may include side guide members toalign sides of the strings.

Subsequently, the ECA 4014 is cured by applying thermal energy to thejoint at S3908. After the ECA 4014 is cured, the finished string isremoved from the fixture at S3910. The string may be removed by liftingtray 4004, which may be removably coupled to the fixture base 4002.

In an embodiment, one or more of the guide members protrudes through oneor more corresponding slot in tray 4004. In one example, at least one ofthe guide members is attached to the base 4002, while at least one otherguide member is attached to the tray 4004.

One or more of the guide members may be, for example, a rail, a wire, acolumn with a cylindrical, rectangular, or other polygonalcross-section, etc. In some embodiments, no tray is present, or one ormore side of the tray may be disposed within the guide members so thatno or few slots are present in the tray. Persons of skill in the artwill recognize that numerous specific embodiments of the guide, base andtray elements of the alignment fixture 4000 are possible.

In an example, the present invention provides a method of manufacturinga solar module apparatus. The method includes providing a photovoltaicstring, the photovoltaic string comprising a plurality of strips from 2to 45, each of the plurality of strips being configured in a seriesarrangement with each other, each of the plurality of photovoltaicstrips having a substantially similar width and substantially similarlength, the photovoltaic string comprising a first bus bar and a secondbus bar, each of the plurality of strips being configured using anelectrically conductive adhesive (ECA) material to another one of theplurality of strips to mechanically connect the plurality of stripstogether. The method includes applying DC power to the first bus bar andthe second bus bar to initiate an emission of electromagnetic radiationfrom each of the photovoltaic strips. The method includes capturing animage of the photovoltaic string to identify at least one of thephotovoltaic strips that has a darker image to identify a defectivephotovoltaic strip. The method includes applying thermal energy to theECA material to change a state of the ECA material to release the ECAmaterial from a pair of the photovoltaic strips to remove the damagedphotovoltaic strip and removing any residual ECA material from the goodphotovoltaic strip(s) adjacent that was adjacent to the damagedphotovoltaic strip. The method includes aligning the photovoltaic stringwithout the damaged photovoltaic strip, and a replacement photovoltaicstrip that replaces the damaged photovoltaic strip; and curing areapplied ECA material on the replacement photovoltaic strip to providethe photovoltaic string with the replacement photovoltaic strip.

In an example, the aligning comprises aligning a first portion of thephotovoltaic string to an alignment member; applying the ECA material onthe first portion of the photovoltaic string; aligning the replacementphotovoltaic strip to the first portion of the photovoltaic string;applying the ECA material on the replacement photovoltaic strip;aligning a second portion of the photovoltaic string to the replacementphotovoltaic strip; and thereafter performing the curing of thereapplied ECA material.

In an example, the DC power comprises a voltage ranging from 10 to 50Volts and a current ranging from 0.5 to 10 Amps.

In an example, the ECA material is an electrically conductive adhesive.

In an example, the thermal energy is provided by conduction, convection,or radiation to a temperature ranging from 180 to 300 Degrees Celsius.

In an example, the method is a repair process.

In an example, each of the photovoltaic strips is derived fromseparating a solar cell into five strips of similar size and shape.

In an example, the damaged photovoltaic strip has a defect consisting ofat least one of a crack, a broken section, a bad electricalinterconnect, a defective photovoltaic material, or a short or opencircuit.

In an example, the image is captured in an electromagnetic radiationrange including infra-red.

In an example, the good photovoltaic strip emits a substantially evenimage that has been captured and is homogeneous along an entirety of asurface region of the good photovoltaic strip.

In an example, the photovoltaic string is configured with a plurality ofphotovoltaic strings in a module before a lamination process.

In an example, the thermal energy is provided selectively to localizeheat to the EVA material, while maintaining other portions of the stripsubstantially free from thermal energy.

In an example, one or more of the steps can occur automatically orcontinuously from step to step.

While the above is a complete description of specific embodiments of theinvention, the above description should not be taken as limiting thescope of the invention as defined by the claims.

It is understood that the examples and embodiments described herein arefor illustrative purposes only and that various modifications or changesin light thereof will be suggested to persons skilled in the art and areto be included within the purview of this application and scope of theappended claims.

The invention claimed is:
 1. A method of manufacturing a solar moduleapparatus comprising: providing a photovoltaic string, the photovoltaicstring comprising a plurality of from 2 to 45 strips, each of theplurality of strips being configured in a series arrangement with eachother, each of the plurality of photovoltaic strips having asubstantially similar width and substantially similar length, thephotovoltaic string comprising a first bus bar and a second bus bar,each of the plurality of strips being coupled to another one of theplurality of strips using an electrically conductive adhesive (ECA)material to mechanically connect the plurality of strips together;detecting the presence of at least one defective strip in thephotovoltaic string; applying thermal energy to the ECA material tochange a state of the ECA material to release the ECA material from apair of the photovoltaic strips to remove the defective photovoltaicstrip; removing any residual ECA material from one or more goodphotovoltaic strip that was adjacent to the defective photovoltaic stripin the string; aligning the photovoltaic string without the defectivephotovoltaic strip, and a replacement photovoltaic strip that replacesthe defective photovoltaic strip; and curing a reapplied ECA material onthe replacement photovoltaic strip to provide the photovoltaic stringwith the replacement photovoltaic strip.
 2. The method of claim 1wherein the aligning comprises: aligning a first portion of thephotovoltaic string to an alignment member; applying the ECA material onthe replacement photovoltaic strip; aligning a second portion of thephotovoltaic string to the replacement photovoltaic strip; and curingthe reapplied ECA material.
 3. The method of claim 1, wherein the ECAmaterial is a thermosetting acrylate adhesive.
 4. The method of claim 3,wherein the ECA material is a heat cured adhesive that is loaded withconductive metal particles.
 5. The method of claim 1 wherein the thermalenergy is provided by conduction, convention, or radiation to atemperature ranging from 150 to 300 degrees Celsius.
 6. The method ofclaim 5, wherein the thermal energy is provided by conduction using aheat source that is heated to from 150 to 250 degrees Celsius.
 7. Themethod of claim 1, wherein each of the photovoltaic strips is derivedfrom separating a solar cell into five strips of similar size and shape.8. The method of claim 1, wherein the defective photovoltaic strip has adefect consisting of at least one of a crack, a broken section, a badelectrical interconnect, a defective photovoltaic material, or short oropen circuit.
 9. The method of claim 1, wherein detecting the presenceof the at least one defective strip includes: applying DC power to thefirst bus bar and the second bus bar to initiate an emission ofelectromagnetic radiation from each of the photovoltaic strips;capturing an image of the photovoltaic string to identify at least oneof the photovoltaic strips that has a darker image and therefore adefective photovoltaic strip than a good photovoltaic strip to identifythe defective photovoltaic strip.
 10. The method of claim 9, wherein theimage is captured in an electromagnetic radiation range includinginfra-red.
 11. The method of claim 10, wherein the good photovoltaicstrip emits a substantially even image that has been captured and ishomogeneous along an entirety of a surface region of the goodphotovoltaic strip.
 12. The method of claim 9, wherein the DC powercomprises a voltage ranging from 10 to 50 Volts and a current rangingfrom 0.5 to 10 Amps.
 13. The method of claim 1, wherein the photovoltaicstring is configured with a plurality of photovoltaic strings in amodule before a lamination process.
 14. The method of claim 1, whereinthe thermal energy is provided selectively to localize heat to the ECAmaterial, while maintaining other portions of the strip substantiallyfree from thermal energy.
 15. The method of claim 1, wherein, after thethermal energy is applied to the ECA, mechanical force is applied to ajoint which is bonded by the ECA material to mechanically separate thedefective strip from a portion of the string that includes non-defectivestrips.
 16. The method of claim 14, wherein the portion of the stringthat includes non-defective strips is retained in a fixture, and thedefective strip is exposed by an orifice of the fixture.
 17. The methodof claim 15, wherein the thermal energy is applied to the joint byplacing the joint in contact with a heated structure.
 18. The method ofclaim 14, wherein the mechanical force is a force moment that is appliedby rotating the portion of the string that includes non-defective stripsrelative to the defective strip.
 19. The method of claim 1, wherein thereplacement strip is an end strip of a second string portion comprisinga plurality of non-defective strips.
 20. The method of claim 1, whereinthe ECA bonds an upper surface of a first string to a backside surfaceof a second string in an overlapped joint.